Furnace



A ril 8, 1924,-

H. A. KUNITZ FURNACE 2 SheetsSheet 1 Filed Oct. 6, 1920 IINVENTOR ATTORN EYS H. A; KUNITZ' April .8, 192 1;

FURNACE Filed Oct. 6 1920 2 Sheefis-Sheet 3 f ATTORNEYS.

Patented Apr. 8, 1924.

UNETE S T A T HANNIBAL A. KUNITZ, OF SPRINGFIELD, MASSACHUSETTS, ASSIG'NOR TO ADVANCE FURNACE & ENGINEERING COMPANY, OF SPRINGFIELD, MASSACHUSETTS, A COB- PORATION OF MASSACHUSETTS.

FURNACE.

,Application filed October 6, 1920. Serial No. 415,004.

T all whom it may concern: 7

Be it known that I, HANNIBAL A.

KUNITZ, born in Tunis of a German father and French mother and i not positively knowing of what citizenship I am, but having formally declared my intention of becoming a citizen of the United States in accordance with the Fnited States naturalization laws, and liming diligently prosecuted my application for United States citizenship to date, and now residing at Springfield, county of Ilampden, and State of Massachusetts, United States of Amer ica, have invented new and useful Improve ments in Furnaces, of which the following is a specification.

This invention relates to furnaces, such as are used for heating various articles preparatory to hardening, tempering, annealing, or other heat-treating operations. The invention is particularly concerned with furnaces of thistype which are provided with means for automatically introducing the articles into, conveying them through and discharging them from the furnace.

The invention has for one object to pro vide ina furnace of the class described improved conveying means operable to move in a step-by-step manner, and to move them from polnt to point along the floor of the furnace without dragging them along such floor, thus preventing wear on such floor, which, being of heat-resisting material, tends to wear. relatively rapidly.

More particularly, it is an object of the invention to provide in the furnace a longitudinally-movable transporter for the articles and a vertically-movable support there-- for, both being movable intermittently and. so coordinated that the support is raised so that the transporter lifts the articles free from the floor of the furnace, the transporter is moved to advance the articles while in lifted position, the support is lowered at the end of the advance movement of the transporter to deposit the articles on the floor of the furnace, and thereafter the transporter is returned to its original position Another object of the invention is to provide a table upon which the heated articles are delivered and to provide means for ti1t ing such table to discharge the heated arti cles, theretofore deposited .on it, upon or into a suitable receiver, which may in some instances be a quenching tank, for example.

A further object of the invention is to provide improved means for controlling the operation of the transporter and movable support so that they operate in coordinated sequence, as above described.

,Another object is to provide controlling mechanism capable of automatically oper-- ating the transporter and its support insuccessive cycles with predetermined intervals of rest between the cycles.

A further object is to provide means for varying the intervals of rest between the cycles of operation, whereby the time inter val during which articlcsremain n the fur nace (during the periods of inaction of the conveyingmeans) may be varied to suit the character of the particular, articles being heat treated.

A further object is to provide, in a furnace of the type described, generally improved mechanical structure.

Other objects and advantages will appear in the following description and in the illustrative embodiment of the invention in the accompanying drawings, in which- Fig. 1-is an elevational view, partly in section, of the furnace;

Fig. 2 is a crosssectional view taken on the line 22 of Fig. 1; and

Fig. 3 is a diagrammatical view illustrative of the means for vcoordinating the movements of the transporter and its movable support and for controlling the intervals between successive cycles of operation thereof.

Referring to these drawings; the furnace,

shown in Figs. 1 and 2, may be variouslynace includes spaced side frames a sup ported by a base-plate b which, in turn, is supported from the floor by suitable pedestals c. The space between frames (6 and base-plate b is filled in with suitable heatresisting material, such as fire-brick or the like, leaving a continuous passage (1 above the floor e of the furnace. The left-hand portion of passage (Z, as viewed in Fig. 1, is somewhat enlarged, as shown, to form the main heating chamber, while the righthand portion of passage (5 constitutes a preheating chamber.

The floor 6 of the furnace is provided throughout the entire length with at least two parallel and relatively deep grooves f, in which are received the longitudinallymovable transporter and its vertically-movable support. The latter comprise longitudinal bars 5, of; suitable material, which lie in the lower portions of grooves f, and underlie the transporters, which are shown at 6. The bars 5, being at some distance below the heating chambers and only indirectly exposed to the heat, may, for example, be made of castiron, although there are preferably provided in these bars one or more passages 7 through which" a sun.- able cooling fluid may be circulated. Since bars 5 are adapted to move vertically, the passages 7 are connected by flexible pipes 8 and 9 to the inlet and discharge pipes 10 and 11, respectively, for the cooling fluid.

,The bars 5 and the transporters 6 thereabove preferably fit as closely as is feasible in the grooves f to minimize the degree of heat to which they are subjected.

The transporters 6 consist of bars which are similar but longer than the bars 5. Preferably, they are composite, as indicated in Fig. 2. That is, each transporter may includea lower metallic portion 12 and an upper portion 13, of heat-resisting material, such as firebrick or the like, which are preferably laid in the groov'c shown in the upper face of the member 12 and held together and to the member 12 by fireclay or the like, which is represented at 14. The members 12, in their lower faces, are preferably provided with longitudinal grooves 15 of curved cross-section, in which are received the upper portions of balls 16, which rest and ride in grooves 17 formed in the upper faces of the supporting bar 5. Projections 18 in grooves 17 maintain the balls 16 in the desired separated relation. Other means o f supporting the transporters 6 from the 'supporting bars 5 may be employed, if desired,

although the described means is preferred.

Each of the supporting bars 5 is secured to the upper ends of a series of vertical rods 19 which extend downwardly through and below the furnace and are secured to a longitudinal beam 20. Above the .beam. and arranged one near each end thereof, are

25, in which is received a pin 26 fixed to the base-plate Z) of the furnace, whereby the lifting frame and connected supporting bars 5 are constrained to move in a vertical path.

The vertical movement of the lifting frame and vertically-inovablc support is accomplished by simultaneously rocking the shafts 21. To this end, toggle levers 28 are pr0- vided, one fixed to each shaft 21, and extending inwardly from the ends of the furnace in opposite directions toward a common point. The free end of each lever 28 is connected by a link 29 to the lower end of a piston-rod 30. a piston (not shown) which is movable in a cylinder '31 fixed to one of the side frames a. Fluid under pressure may be admitted to and exhausted from each end of cylinder 31 to lift rod 30 and thus the vertically-movable support or to lower said rod and support.

To this end, a two-way valve 32 (conventionally indicated in Fig". is provided, and pipes and 34 lead from valve 32 to opposite ends of cylinder 31., An inlet pipe 35, adapted for connection to a source of fluid under pressure, is provided, as well as an exhaust pipe 36. The valve is movable by a lever 37 into one position, wherein the inlet pipe 35 is connected to pipe 33 and the exhaust pipe to pipe 34, whereby rod 30 will be moveddownwardly. The valve is also movable to another position, wherein pipe 33 is connected to the exhaust pipe 36 and pipe 34 to the inlet pipe 35, whereby rod 30 will be moved upwardly. The actuation of valve 32 is controlled by mechanism to be hereinafter described.

The transporter is movable in a similar manner, a cylinder 38 for fluid under pres sure being mounted on a base 39 at a distance'from the furnace. The piston-rod 40 of cylinder 38 is connected by a link 41 to one end of the transporter 6, whereby vertical movement of the latter is permitted with- ,out interference with the means for effecting the horizontal movement.

A two-way valve 42 is provided for cylinder 38 and pipes 43 and 44 lead from this valve to opposite ends of cylinder 38.- Inlet and exhaust pipes 45 and 46, respectively, are provided for valve 42. as well as an actuating handle 47. Valve 42 is movableto two positions, in one of which pipe 45 is connected to pipe 43 and pipe 46 to pipe 44,

The latter is provided with 'rods 30 and 40 move.

as illustrated, whereby rod 40 will be moved inwardly (to the left as viewed in Figs. 1 and 3). In the other position, pipe is connected to pipe 44 and pipe 46 to pipe 43, whereby rod 40 will be moved outwardly.

The means for automatically operating the valves-32 and 42 to coordinate the movements of the transporter and its verticallymovable support will next be described. As shown, each cycle of operation of the transporter and'its support is started electromagnetically, after which the operation of the support controls the subsequent operation of the transporter, and vice versa. To this end, the valve lever 37 is actuated electromagnetically, as by a solenoid 48, the core 49 of which actuates a pivoted bellcrank 50, which, in turn. moves lever 37. On energization of solenoid 48, valve 32 will be moved from the illustrated position into position to connect pipe 35 to pipe 34, whereby rod 30 and thus the vertical support will be lifted.

, Solenoid 48 is connected by wires 51 and 52 to a battery 53 and a switch lever 54, respectively. Switch lever 54 is movable to connect wire 52 to any one of a plurality of wires 55 which terminate in fingers 56. Each finger 56 lies in the path of one or more contacts 57 mounted on a rotatable drum 58. All of these contacts are electrically connected together in a suitable manner and to a. wire 59 leading to battery 53. For example, drum 58 might be metallic and wire 59 connected to the drum. as conventionally indicated.

Drum 58 is rotatable, through speed-reducing gearing conventionally indicated at 60, from an electric motor 61, and turns in the direction of the arrow. Drum 58 is designed to turn at a speed relatively slow in comparison to the speed at which the piston The speed of the latter may, of course, be varied by regulation of the area of the exhaust ports in a well-known manner. The, intent is to have the drum move considerably slower than ordinary speeds at which the piston rods would move. For example, while the entire cycle of operation of the piston rods 30 and 40 (two strokes Oteach) is being accomplished, drum 58 turns only a relatively short distance, such, for example, as is indicated by dimension as in Fig. 3.

The motor 61 is electrically connected by a wire 62 to one terminal of a double pole switch 63 and by a wire 64 to one terminal of a single pole switch 65, the other terminal of the latter being connected by a wire'66 to the other terminal of the switch 63. Switch 63, when closed, connects the motor 61 (provided switch 65 is closed as illustrated) to a suitable source of electromotive force. Switch 65' is automatically closed when piston-rod 40 moves into its inner position, as by a plunger 67,engageable by the piston 40' on rod 40, which plunger actuatis switch 65 through a pivoted lever 68. A spring 69 moves lever 68 in the opposite direction and automatically opens switch 65 as soon as pissubjected, a succeeding cycle is not started immediately but various predetermined time intervals are purposely allowed to elapse. To control the duration of such time intervals is the function of drum 58. It has been shown that the motor 61 is set in motion at the end of each cycle by the closing of switch 65 and thus drum 58 commences its rotation, or partial rotation, in. the illus trated direction. It has also been shown that the next cycle of operation will be started upon the energization of solenoid 48. This will not occur until one of the fingers 56 (that to which wire 52 is electrically connected by the switch lever 54) engages the first of its scries'of contacts 57. Thus, an interval elapses between the end of one cycle and the start of a succeeding cycle.

It is also a function of the drum 58 to permit. variation of the time interval elapsing between successive cycles. To this end, the several series of contacts 57 and fingers 5 6 and the switch 54 for selectively bringing any one finger into effective action are provided as heretofore described. As many series of contacts 57 and. fingers 56 may be provided as desired and'the disposition of the contacts 57 on the drum may also be varied, depending upon the various time intervals desired. As shown, the first series (at the extreme right of drum 58) consists of only one contact. The next series consists of two contacts, and succeeding series of three and four contacts. Thus, with switch lever 54 in the illustrated position, nearly one complete revolution of drum 58 is required to energize solenoid 48, or a maximum time interval. Vith switch lever 54 moved to bring the second finger 56 into effective action, substantially half a revolution of drum 58 is required, and with the other two fingers substantially one-third and one-fourth of a revolution, respectively.

On energization of solenoid 48, valve 32 is so moved that rod 30is lifted, and the lifting of rod 30 is made to control the operation of valve 42. Thus, a flexible cable 70 is fixed atone end torod 30 and travels over various pulleys 71, being provided at its other end with a weight 72, whereby the cable 70 is maintained tautat all times. Cable 70 passes in close proximity to, and

preferably loosely through, the Valve-actuating lever 47 and has fixed thereon an abutment 73, which is so located that it engages and moves the lever 47 into position to connect pipe 44 to the inlet pipe 45 and pipe 43 to the exhaust pipe 46. This action is so timed that rod 40 is caused to move outwardly at or about the time when rod 30 reaches the end of its upward stroke. Due tospace limitations, Fig. 3 is not drawn to scale, and the cable 70, as well as another cable to be described, has been broken away. The illustration, therefore, is necessarily diagrammatical and conventional, but when taken with this descri tion will sufiice to enable one skilled in t e artto understand this portion of the invention.

After rod 30 reaches its upper limit of movement, it is held there by fluid pressure until valve 32 is later moved, which occurs only after an outward movement of rod 40. Meanwhile, rod 40 advances on its outward stroke and such stroke is made to control the movement of valve 32 in the following manner. A flexible cable 74, fixed at one end to rod 40, or some connected part, travels over pulleys 75 and is provided at its other end with a weight 76, for the purpose of maintaining cable 74 taut at all times. Cable 74 passes into close proximity to, and preferably through, the bellcrank 50, and has fixed thereto an abutment 77, which engages and moves bellcrank 56 so as to move valve 32 into such position that inlet pipe 35 is con nected to pipe 33 and exhaust pipe 36 is connected to pipe 34, whereby rod 30 will be moved downwardly. This movement of valve 32 is so timed that the rod 30 commences to move downwardly at or about the time when rod 40 reaches the limit of its outward stroke.

As rod 30 moves downwardly, cable moves as before and a second abutment 78, fixed thereon, eventually engages the valveactuating lever 47 (which is now in its extreme right-hand position) and moves it back into the illustrated position, whereby rod 40 is started on its inward stroke. The movement of valve 42 is timed so that rod 40, which has been held in its outward position by fluid pressure during the descent of rod 30, commences its inward stroke at or about the time when rod 30 reaches its lowermost position.

, As roil 4O continues to move on its inward stroke, its piston 40, at or about the end of such stroke, engages plunger 67 and closes switch 65. Thus, motor 61 is energized and drum 58 again started in its movement. After the elapse of a predetermined interval, solenoid 48 will be again energized and a succeeding cycle of operation will ensue. Whenever it is desired to stop the machine, switch .63 is opened, whereby the piston rods 30 and 40 will come to rest at the ends of their respective cycles of movement and fur ther cycles of operation cannot occur'until the switch 63 is again closed. The articles to be heated are placed. upon the spaced brackets 80 fixed to frames at at one end of the furnace. The upper faces of these brackets, on which the articles, or as shown, trays 81 containing the articles, rest, are disposed in a horizontal plane above the level of the transporters 6 when in their lower position and somewhat below the level of the transporters when in their upper position. It follows that upon the start of one of the described cycles of operation, the transporters 6, being lifted by the rising of their vertical supports, rise and engage tray 81. lifting it free of the'brackets 80. After tray 81 has been lifted away from the latter, the transporters 6 commence their longitudinal movement and carry tray 81 into the furnace. The tray 81 is thus carried into the preheating chamber of the furnace or into the righthand position indicated by dotted lines in Fig. 1. Having been moved to such position, the tray 81 is deposited upon the floor c of the furnace by the lowering of the transporters and their vertically-movable supports. After these transporters have moved downwardly away from tray 81, they are then moved outwardly into their original position ready to pick up another tray 81 and carry it into the preheating chamber. When this occurs, the tray 81 formerly left in the preheating chamber is again picked up and deposited in the main heating chamber of the furnace in the left-hand dotted line position, and on the next-succeeding operation it is moved entirely out of the furnace. Thus, the trays are moved step-by-step through the furnace and, by reason of the vertical lifting and lowering movements imparted to them prior to and after the longitudinal inward movement of the transporters, they are never allowed to drag along the floor (Z of the furnace to cause wear thereof.

\Vlnle trays 81 have been illustrated as a desirable means for containing the heated articles, the articles may in many cases be directly engaged and moved by the transporters. The trays are used for small articles and may be used for any and all articles that can be deposited in them, although if the articles are generally fiat and long enough to bridge across one of the grooves f, the trays may, if desired, be dispensed with.

The delivery opening of the furnace, opening as it does directly into the main heating chamber, requires some means to close it except during the passage of the articles. The entrance to the furnace, being more re mote from the main heating chamber, the provision of a closure is less important and may, if desired, be entirely dispensed with, as illustrated. As a closure for the delivery opening of the furnace, a sliding door 83 is provided, which normally is in closed position as illustrated but is automatically movable to open position just prior to the longitudinal movement of the transporters. Door 83 is suspended by a cable 84, the upper end of which is fixed to a curved segment 85 pivotally supported by a bracket 86 from the top of the furnace. Segment 85 is movable by a lever 87 which is connected by a link 88 to a lever 89 fixed to one of the rockshafts 21. Thus, as thetransporters 6 rise, prior to their inward longitudinal movement, door 83 is lifted and as the transporters descend after such longitudinal movement, door 83 closes.

The articles or their trays 81 are moved out of the furnace onto a table 90 and may be removed therefrom in any desired way. Preferably, table 90 is mounted to tilt after a tray has been deposited thereon, whereby the articles or trays 81 may be discharged into or onto some suitable member. Such member may, according to one feature of the invention, be a receptacle 91 and such receptacle may, if desired, constitute a quenching tank. The table 90 is pivoted at 92 to brackets 93 fixed to the delivery end of the furnace. Fixed to the table 90, or to pivot 92, is a lever 94, the free end of which is connected by a link 95 to the upper end of a lever 96, fixed to one of the rock-shafts 21. Thus, as the transporters 6 rise to'lift the articles, the table 90 is moved into horizontal position, as indicated by dotted lines, so as to be in readiness to receive a tray on the subsequent inward longitudinal movement of the transporters. As the latter descend, the articles move toward the table and, at the same time, the table commences to tilt, so that the articles are discharged into receptacle 91.

The operation of the furnace will sufiiciently appear from the foregoing description.

The invention has been disclosed herein, in an embodiment at present preferred, for illustrative purposes, but the scope of the invention is defined by the appended claims rather than by the foregoing description.

What I claim is,

1. In a furnace, a frame, a longitudinallymovable transporter for moving articles intermittently through said furnace, a verti-' cally-movable support for said transporter, oppositely-extending levers pivoted to said frame adjacent to opposite ends of said furnace and extending inwardly to a point adj acent the transverse center line of the furnace, connections between said levers and said support, means comprising a lifting cylinder for actuating said levers to raise said-support, and means for advancing the transporter when said support is in raised position.

' 2. In a furnace, a longitudinally-movable transporter for moving articles through said furnace, a tilting table for receiving and discharging articles from the furnace, mearis for raising and advancing the transporter, and means operated in conjunction with said first-named means for tilting said table.

3. In a furnace, a longitudinally-n'iovable transporter for moving articles through said furnace, means for raising the transporter prior to the longitudinal movement thereof and for lowering it after such movement, a tilting table movable from position to receive articles from said transporter to a position to discharge such articles, and means operable by the raising and lowering of said transporter to move said table from one position to the other.

4. In a furnace, a longitudinally-1novable transporter for moving articles through said furnace, receiving means for the heated articles, a tilting table for receiving articles and discharging them upon said receiving means, means for raising and advancing the transporter, and means operated in conjunction with said first-named means for tilting said table.

5. In a furnace, a longitudinally-movable transporter for moving articles through said furnace, a quenching tank, a tilting table for receiving articles and discharging them into said quenching tank, means for raising and'advancing the transporter, and means operated in conjunction with said firstnamed means for tilting said table.

6. In a furnace, a transporter to carry articles therethrough, means for raising and lowering the transporter, means for reciprocating the transporter longitudinally, a controlling device for each of said means, mechanism for automatically operatingsaid de vices in proper sequence so that the transporter moves through one complete cycle of operation and then comes to rest, and controlling means for said mechanism automatically operable after a predetermined time interval to start it and cause another cycle of operation of said transporter.

7. In a furnace, a transporter for the articles, means for reciprocating the transporter longitudinally, means for raising and lowering it; controlling mechanism to cause each means to operate inproper sequence so that the transporter rises, advances, descends, retracts and then stops; means for starting said mechanism at a predetermined time interval after the transporter comes to rest, and means for varying the last named interval.

8. In a furnace, a transporter for the articles, means for reciprocating the transporter longitudinally, means for raising and lowering it; controlling mechanism to cause each means to operate in proper sequence so that the transporter rises, advances, descends, retracts and then stops; and means Ill operable by the last-named movement of the transporter to start said mechanism after a predetermined interval.

9. In a furnace, a transporter for the articles, means for reciprocating, the transporter longitudinally, means for raising and lowering it; controlling mechanism to cause each means to operate in proper sequence so that the transporter rises, advances, de-

scends, retracts and then stops for a predetermined and substantial period of time,

means operable by the last-named movement of the transporter to start said mechanism after a predetermined interval, and timing mechanism automatically operable at the end of the last-named movement to start said controlling mechanism at a predetermined time after the stopping of the transporter.

HANNIBAL A. KUNITZ. 

